pairing between signal and receiver synthesis and
TRANSCRIPT
Hormones and Receptors
• Pairing between signal and receiver • Synthesis and processing of Hs • Regulation of Hs, Rs • Many are closely related
• Questions???
Assignment • Textbook pages to reinforce today (pg. 109-130)
• Two extra credit assignments posted • Nothing quizzable for Tuesday
BIG questions • Why do organisms pair up to reproduce?
• Why should this pairing up mean that they take 2 distinct forms?
• How do they come to take these distinct forms -- female and male?
• Sexual Dimorphism -- different forms for female, male; how far does this extend?
• Sexual Differentiation -- process of becoming different
• Developmental program
sex determination
• Temperature in turtles
• Social factors in fish
• For mammals, genetic determination (XX or XY)
• Until 1 month, no differences = indifferent gonad ���Sry gene makes Sry protein ���à indifferent gonad to be testis. ���
• Absence of Sry protein allows gonad to hang out - later becomes ovary ���
• Pattern is called single anlage - the F/M organ derives from same structure
• If testis is present, it secretes
– Testosterone (steroid) – Anti-Mullerian Factor/Hormone (= Mullerian
Inhibiting Hormone) (protein)
• If testis is present, it secretes
– Testosterone (steroid) – Anti-Mullerian Factor/Hormone (= Mullerian
Inhibiting Hormone) (protein)
• T à DHT (by enzyme) – Growth of penis/maturation of scrotum
• Dual anlagen: – Wolffian ducts - epididymis etc. – Mullerian ducts - uterus, vagina, fallopian tubes ���
• Single anlage: – Genital tubercle – clitoris OR penis – Genital folds – labia OR scrotum
Environmental influences
• Red deer – High status ==> more males – Stress ==> more females
http://www.sciencedirect.com/science/article/pii/S0018506X1200044X Small predictor of toy choices at 14 months???
Puberty Body changes Hormonal changes Behavioral changes
Puberty
Is SRY responsible for everything?
Variations • Androgen Insensitivity Syndrome
– Mutation on X chromosome • Affects males only
• Gonad? • Sex steroids? • Ducts? • Genitals? • Gender Identity?
Nelson CP and Gearhart JP (2004) Current views on evaluation, management, and gender assignment of the intersex infant. Nat Clin Pract Urol 1: 38–43 doi:10.1038/ncpuro0028
Figure 3 Newborn genetic female (46XX) with congenital adrenal hyperplasia due to complete 21-hydroxylase deficiency
Variations • Congenital Adrenal Hyperplasia
– Significant for females • Gonad? • Sex steroids? • Ducts? • Genitals? • Gender Identity?
Figure 4. Two patients with 5a-reductase deficiencies. Two patients with 5a-reductase deficiencies. A, Before puberty, the patient presents as a phenotypic female. B, After puberty, a normal male body habitus develops. Note the muscular development and masculine appearance in response to endogenous testosterone. (Adapted from Peterson [27].)
Variations • 5 α reductase deficiency
– What does this do? • Gonad? • Sex steroids? • Ducts? • Genitals? • Gender Identity?
Figure 1. Patient with Klinefelters syndrome (XXY karyotype). Patient with Klinefelters syndrome (XXY karyotype). Note the relatively normal masculine appearance except for gynecomastia.
Variations • Klinefelter’s syndrome
– Extra X chromosome
• Gonad? • Sex steroids? • Ducts? • Genitals? • Gender Identity?
Variations • Persistent Mullerian Duct Syndrome (PMDS)
Feminizing Genital Reconstruction: Experience with 52 Cases of Ambiguous Genitalia A. Al-Bassam1, A. Gado1 1 Division of Pediatric Surgery, Department of Surgery, King Khalid University Hospital, Riyadh, Saudi Arabia
Timeframe
• Will hormones reverse your sex in adulthood? Any part of it?
• Permanent effects (organizational) • Reversible effects (activational)